Orthodontic torquing appliance



Feb. 22, 1966 MUlR 3,235,965

ORTHODONTI C TORQUING APPLIANCE Filed March 6, 1963 2 Sheets-Sheec 1Feb. 22, 1966 R. J. MUIR 3,235,965

ORTHODONTIC TORQUING APPLIANCE Filed March 6, 1963 2 Sheets-Sheet 2 Q \H1N VEN TOR Fave 4 40 (fl/0M United States Patent Ofilice 3,235,965Patented Feb. 22, 1966 3,235,965 ORTHQDONTIC TORQUING APPLIANCE RichardJ. Muir, 12 Oak Road, Santa Cruz, Calif. Filed Mar. 6, 1963, Scr. No.263,209 4 Claims. (CI. 3214) This invention relates to orthodontictorquing appliances, and more particularly to a torsion spring mechanismmountable to an arch wire in orthodontia.

In orthodontia, in which misalignment of teeth is corrected byapplication of controlled forces to selected teeth, it often occurs thata single orthodontic technique is not well :adapted to correct themisalignment of teeth in a particular patient. Each orthodontictechnique, such as the edgewise, lightwire (Begg), universal, ortwin-wire technique, is best adapted to correct a specific type ofmisalignments or to apply force in a particular manner. Each of thesetechniques, however, provides that the force applied to a given toothhas a reaction on an adjacent tooth. In the majority of situations thisis desired and judicious selection of the action and reaction of theforces is relied upon to move the teeth to correct for misalignment. Forexample, in the Begglightwire technique a round arch wire is formed intoloops which are disposed at selected locations relative to the teeth.The loops act as springs, the alignment of a loop :and the degree ofdefiection from a relaxed or unstressed condition determining the natureof movement of the teeth between which the loop is disposed. Similarly,in the edgewise technique a square arch wire is engaged in rectangularlyconfigured slotted brackets secured to selected teeth, the arch wirebeing torqued to impart force to the brackets.

In each of these methods, however, it is not readily possible to applycontrolled force to :a single tooth to cause the tooth crown to moveposteriorly in a pivoting motion relative to the root of the tooth. Incases where incisor teeth tilt lingually, the limitations of existingorthodontic appliances are especially restrictive. The present inventionprovides simple, effective and efficient means whereby a single toothmay be moved pivotally substantially independently of adjacent teeth.The apparatus of the present invention is especially effective incorrecting lingual tilting of crowns of incisors.

Generally speaking, the present invention provides an orthodontictorquing appliance which is engagable with an arch wire disposedlabially of the tooth. The applitance comprises a length of wireconfigured at each of a pair of spaced apart ends for looselycircumferentially engaging the arch wire distally of the tooth along anaxis of the appliance. The appliance axis is coextensive with the archwire over the length of the appliance. The wire defines torque outputmeans intermediate of its ends for engaging the tooth apically of thetooth from the appliance axis. The wire adjacent opposite extents of thetorque output means defines a plurality of coils which engage the archwire along the axis. The wire ex tends in opposite directions distallyfrom the coils to the ends of the wire and defines torque input armssubstantially parallel to the appliance axis.

The above mentioned and other features of the present invention are morefully described in the following detailel description of the invention,taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a plan view of a human maxillary denture showing the torquingappliance of the present invention installed on an orthodontic archwire;

FIG. 2 is a quartering side elevation view of the installation shown inFIG. 1;

FIG. 3 is an idealized cross sectional view taken along line III-III ofFIG. 1 showing the torquing appliance mounted to an arch wire installedaccording to the edgewise technique;

FIG. 4 is an enlarged elevation view of a preferred embodiment of thetorquing appliance according to the present invention adapted for use inthe edgewise technique of orthodontia;

FIG. 5 is a fragmentary elevation view of an end of a second preferredtorquing appliance adapted for use in the edgewise technique oforthodontia;

FIG. 6 is an elevation view of an end of a third pre ferred torquingappliance for use in conjunction with the lightwire technique oforthodontia; and

FIG, 7 is an elevation view of a fourth preferred embodiment of thepresent invention adapted for use with the edgewise technique inorthodontia of the mandibular denture.

Referring initially to FIGS. 1 and 2, maxillary orthodontia 10,incorporating a torquing appliance 11 according to the presentinvention, is illustrated. The auxiliary, or upper jaw, denture includescentral incisors 12 and 13, lateral incisors 14 and 15, cuspid teeth 16and 17, first bicuspids 18 and 19, second bicuspids 20 and 21, and firstand second molars 22 through 25, respectively. The crowns of the 1stmolars, and all teeth between the first molars, are banded, as by band26 on central incisor 12, to mount orthodontic edgewise-type arch wiresupporting brackets 27. An arch wire anchoring bracket 28 is mounted tothe bands engaged with the first molars. An arch wire 29 is engagedcircumferentially and anteriorly of the denture between the first molars22 and 23 and has its opposite ends engaged in the anchoring brackets;the arch wire is disposed in supporting brackets 27 intermediate of itsends.

In the orthodontia illustrated in FIGS. 1 and 2, the arch wire iscircularly cross sectioned to provide an arch wire according to thelightwire technique (see FIG. 3). The arch wire is engaged in arectangularly contoured slot in each of brackets 27 so that a torqueimposed on the arch wire is transferred to the teeth so that selectedteeth are moved relative to adjacent teeth. The arch wire is ligated toeach supporting bracket 27 by fine wires engaged to the cleat-likeconfiguration of the brackets. The ligation technique is conventional inorthodontic practice. but the ligation wires are not shown in thheaccompanying drawings for the purpose of clarity of illustration.

FIG. 4 illustrates a preferred embodiment of the torquing applianceaccording to the present invention. The appliance is fabricated from alength of metallic resilient wire. The wire preferably has a diameter ofabout .012 to .014 inch and preferably is fabricated from stainlesssteel. The wire has a pair of ends 31 and 32 spaced apart distally ofthe midlength or mesial portion of the wire when the appliance isinstalled. The ends of the wire are aligned along an axis 33 whichpreferably is coextensive with arch wire 29 along the elongate extent ofthe appliance. As shown in FIG. 4, a plurality of return-bend torqueoutput means '3437 are formed in the wire intermediate the ends of thewire. The torque output means are also known as anterior loops sincethey engage the anterior or labial surfaces of the teeth acted on by theappliance. Each return-bend torque output means comprises asubstantially U-shaped bend in the wire, each torque output means havingdiverging legs 38 and 39 and a preferably straight portion 40 parallelto axis 33 joining the legs. Portion 40 is provided for engaging thelabial surface of the tooth opposite which it is disposed apically ofthe arch wire, i.e. toward the gingiva or gum from the arch wire. Thelegs of each torque output means terminate in a plurality oftor'sionally resilient coils 41, 42, 43, 44, and 45. Coils 42, 43, and44 are disposed intermediate torque output means 34-37; torsion coils 41and 45 are disposed at opposite ends of the plurality of torsion outputmeans. The torsion output means extend in the same direction from axis33 to have the straight labial surface engaging portions 40 disposedcoaxially parallel to axis 33. The legs of each torsion output meansconverge extending from the respective torsion coils to the labialsurface engaging portions of the return-bend sections of wire 30. Theinternal diameter of each of the plurality of coils 41-45 is greaterthan the maximum cross-sectional dimension of the arch wire so that,when the arch wire is disposed through coils 41-45, the coils looselyand circumferentially engage the arch wire as fulcrums for therespective torque output means and permit movement of the appliancerelative to the arch wire.

Torque input means 46 and 47 extend distally laterally from the coils 41and 45, respectively, away from the torque input means toward the end ofthe wire. In the embodiment of the invention illustrated in FIG. 4, thetorque input means comprise torque arms which are disposed parallel to,but are spaced apart from, axis 33 of the appliance. Each torque inputarm terminates in an arch wire anchor means 48, 49, respectively, at theends of the wire. Preferably, the anchor means are provided in the formof a pair of coils in the wire. The coils of the anchor means are of thesame internal diameter as each of the coils in the pluralities of coils41-45 so that the anchor means coils loosely and circumferen-.

tially engages the arch wire and permits relative movement between thearch wire and the appliance.

Appliance 11 is manufactured by any convenient method, such as upon awire bending machine, to provide the planar configuration illustrated inFIG. 4. After the device has been formed, it is heated in an oven tostress-relieve the wire. The appliance is then ready for installationupon an arch wire. The arch wire is inserted through coils 41-45 and 48,49 axially of the appliance. The arch wire, with the appliance attached,is then ligated to the arch wire supporting and anchoring brackets withthe torque output means of the appliance being disposed adjacent theteeth which are desired to be moved pivotally about their roots.

It was mentioned above that the present invention is particularlyeffective in correcting lingual tilting of incisors. When the arch wireand the appliance attached are mounted to the brackets in a situationsimilar to that illustrated in FIG. 1, the torque output means of theappliance are disposed apically of the arch wire anteriorly of theincisor teeth. Accordingly, the torque input arms 46 and 47 are disposedtoward the occlusal areas of the cuspid and first bicuspid teethdistally of the incisors. The anchor means of the appliance are disposedin the spaces between the first and second bicuspids. As the arch wireis curved to conform to the arch of the denture and the output loops areaccordingly forced out of the plane of the arch, torque is imposed uponthe appliance primarily through the torque input arms which normallytend to be disposed on the convex side of the arch Wire. The occlusalportions of the cuspid and first bicuspid teeth prevent the input torquearms from rotating into the concave aspect of the arch. The forcesimposed in the Wire of the appliance induce the torque output arms toengage the labial surfaces of the incisor teeth apically of the archwire. The reaction of this torsional force is a torque F (see FIG. 3)which induces the root of the engaged tooth to move posteriorly aboutits crown.

Orthodontic techniques are predicated upon the application of controlledforces to selected teeth. The appliance provided by the presentinvention permits controlled forces to be applied to the incisor teethto correct for lingual tilting. The amount of torque imposed upon theteeth may be regulated by the spacing between coils 4145 along axis 33.To increase the imposed torque, the distance between the distal ends ofthe appliance is decreased to move together coils 4145 to increase thelateral distance between portions 40 of the return-bend arms of thetorque output means and axis 33. The appliance is then stress-relieved,either by the orthodonti'st or by the manufacturer of the appliance.Similarly, the imposed torque may be decreased by moving the distal endsof the appliance apart from one another to reduce the effective torquearms of the torque output means.

If it is assumed that central incisor 13 (illustrated in FIG. 1) has itsroot portion protruding farther anteriorly of the denture than theimmediately adjacent teeth, torque output means 36 disposed adjacenttooth 13 will engage the tooth before the torque output means disposedopposite the adjacent teeth engage the adjacent teeth. Accordingly,central incisor 13 is moved pivotally about the arch wire until it isaligned with the adjacent teeth. If desired, the roots of teeth 12, 13,14, and 15 may be pivoted further posteriorly about their crown-sthrough continued application of forces from the appliance. In manyinstances, however, only a single tooth is to be moved by the applianceof the present invention. In such instances the appliance may includeonly one return-bend torque output means. Alternatively, where astandard appliance is provided, the selected torque output means may bedeformed out of alignment with portions 40 of adjacent torque outputmeans toward the tooth so that only the deformed return-bend torque armengages a tooth; the other arms do not engage their teeth as theselected tooth moves under applied force. It is noted at this point thatthe appliance may be used on teeth other than incisors.

It was mentioned above that the internal dimensions of coils 41-45 and48, 49 provide for movable engagement of the appliance with thesupporting arch wire. Such movement is required to allow the applianceto exert continuing force upon selected teeth while the selected teethmove through considerable distances in the denture. If the ends of theappliance Were secured to the arch wire, as by soldering, the amount oftorque which may be applied to the incisors normally is restricted andthe amount of movement of the torque output means angularly about thearch wire is limited. As a result the protruding incisors may move onlya small distance before all of the stored force in the appliance isreleased. In other instances however the torque input arms may beprestressed by soldering the anchor means in position more toward theadjacent teeth than normally to increase the output torque, as wherefriction between the appliance and arch wire must be overcome.

The foregoing description has presented a mechanism which may be used toapply a substantially constant torquing force. The amount of torquingforce is not altered by the response of the teeth to the force applied.As a result, the present invention eliminates the repeated fittingswhich are required when other orthodontic techniques are used bythemselves. The present invention also provides that the force isapplied continuously. In the edgewise technique, for example, the forceis applied initially at greater strength than after the teeth have movedin response to the applied force. It is therefore necessary, ifcontinued movement is desired in the edgewise technique, to apply asecond arch wire. The applied force imposed by the second arch wiredecays rapidly as the teeth move in response to applied force. Thecontinuously non-cyclic applied force provided by the present inventionis particularly significant in that it overcomes the problems associatedwith cyclic applications of force to the teeth undergoing orthodontia.

The specific configuration of apparatus illustrated in FIG. 4 is adaptedfor use with the edgewise technique wherein the arch wire is disposedcentrally of the supporting brackets on hands 26 (see FIG. 3). It istherefore necessary for the torque arms of torque input means 46 and 47,in order to be disposed occlusally of the arch wire, to be offset fromthe axis of the appliance in order to be disposed below the arch wiresupporting brackets. The' ends of the arch wire brackets. In a presentlypreferred form of appliance 11 the distance between axis 33 and portionsis 0.115 inch while the distance of torque input arms 46, 47 from theaxis is .O8.09 inch. The 0.115 inch dimension is especially preferredsince it is not uncommon for the gingiva of a child undergoingorthodontia to depend so far down a tooth that it is necessary to cutthe gingiva away to band the tooth. It is therefore desirable not tohave the torque arm extend unduly far apically of the arch wire eventhough the greatest torque arm possible is desired for mechanicalpurposes. In the same presently preferred embodiment as mentioned above,the extent of portions 40 of torque output means 35 and 36 is 0.187 inchwhile the extent of the corresponding parts of output means 34 and 37 is0.125 inch.

FIG. 5 illustrates an appliance according to the present inventionadapted for use in conjunction with the lightwire technique. In thelightwire technique the arch wire receiving notches in the supportingbrackets are disposed either gingivally or occlusally of the bracketsrather than through the central portion of the bracket. It is thereforepossible for torque arm 51 of torsion input means 52 to be disposedclosely adjacent axis 53 of appliance 50.

Appliance 55 (illustrated in FIG. 6) is a second preferred embodiment ofthe present invention adapted for use in conjunction with the edgewisetechnique. It was mentioned above that the anchor means of appliance 11are disposed in the area between the first and second bicuspid teeth 18,19 and 20, 21, respectively. In cases where misalignment of the teeth inthe denture is severe, the distance distally of the incisors to bepivoted to the space between the first and second bicuspids may be soconsiderable that the anchor means of a standard appliance (FIG. 4) mayfoul the brackets mounted to the first bi'cuspids. Appliance 55 providesa torque arm 56 having a plain or uncoiled end 57. The orthodontist maycoil the end of the appliance about the arch wire at any desiredlocation in the patients mouth to accomplish the result described abovewith appliance 11.

The foregoing discussion and explanation of the invention has been inconjunction with a maxillary denture. The invention, however, may beused in conjunction with a mandibular denture, i.e. the tootharrangement in the lower jaw of a patient. In such a case, however, thetorque input means and the torque output means are disposed on the sameside of the axis of the appliance, rather than on opposite sides of theaxis as illustrated in FIG. 4. FIG. 7 shows a mandibular form of thepresent invention in appliance 60 which has an axis 61 defined by aplurality of torsionally resilient coils 62 disposed between a torqueoutput means 63 and a torque input means 64 (similar to the torque inputmeans illustrated in FIG. 6). The mandibular appliance is installed withthe return-bend torque output means 63 extending apically of the toothfrom axis 61. Torque input means 64 is also disposed below the axis ofthe appliance and below the arch wire upon which the appliance issupported.

In many cases the degree of eruption of the tooth to be acted upon by anappliance according to the present invention is not such as to permitdirect use of a standard appliance, such as that illustrated in FIG. 4.The lateral distance between arch wire 29 and the gingiva may be lessthan the lateral distance between axis 33 of the appliance and coaxiallyaligned portions 40. In such an instance, it is a simple expedient tobend the legs of the torque output means to reduce the torque arm of theoutput means to clear the gingiva and to bear directly upon the labialsurface of the teeth.

While the invention has been described above in conjunction withspecific apparatus, it should be apparent to those skilled in the art,and particularly to Orthodontists using the present invention, that theappliance described above may be modified to accommodate particulartreatment situations without departing from the scope of the presentinvention. The foregoing description is presented merely for thepurposes of explanation and example and is not to be considered asrestrictive of the scope of the present invention.

What is claimed. is:

1. A structural system for effecting tilting of a persons toothcomprising, in combination, a metal band adapted to be mounted aroundthe tooth, a bracket affixed to the band and adapted to extendanteriorly of the tooth, the bracket defining a channel in its labialaspect, an arch wire extending through the channel, means connected tothe bracket retaining the arch wire in the channel, the arch wireextending laterally of the bracket to ends spaced substantially from thebracket, means for attaching respective ends of the arch wire to twoother teeth spaced from said tooth, the arch wire curving arcuatelybetween its ends, and a length of resilient wire defining intermediateits ends two groups of helical coils circumferentially of the arch wire,the groups of coils loosely circumferentially engaging the arch wirelaterally of and proximate to the bracket, the resilient wire betweenthe groups of coils defining a return-bend loop extending laterally ofthe arch wire, the loop having a portion substantially parallel to thearch wire spaced from the arch Wire, the resilient wire extending fromeach group of coils away from the return-bend. loop along and in spacedrelation to the arch wire to ends of the resilient wire spacedsubstantially from the groups of coils, means securing the ends of theresilient wire to the arch wire, conformance of the elongate extent ofthe resilient wire to the curvature of the arch wire torsionally biasingthe resilient wire between its ends and the groups of coils to producetorquing leverage on the tooth through engagement of said portion of thereturn-bend loop with the tooth when the system is in use effective topivot'the tooth about the connection between the arch wire and thebracket.

2. A structural system for effecting tilting of a persons toothcomprising, in combination, a metal band adapted to be mounted aroundthe tooth, a bracket afiixed to the band and adapted to extendanteriorly of the tooth, the bracket defining a channel in its labialaspect, an arch wire extending through the channel, means connected tothe bracket retaining the arch wire in the channel, the arch wireextending laterally of the bracket to ends spaced substantially from thebracket, means for attaching respective ends of the arch wire to twoother teeth spaced from said tooth, the arch wire curving arcuatelybetween its ends, and a length of resilient wire defining intermediateits ends two groups of closely wound. helical coils circumferentially ofthe arch wire, the groups of coils loosely circumferentially engagingthe arch Wire on opposite sides of and proximate to the bracket, theresilient wire between the groups of coils defining a return-bend loopextending laterally of the arch wire substantially directly from thegroups of coils, the resilient wire extending from each group of coilsaway from the return-bend loop along and in spaced relation to the archwire to ends of the resilient wire spaced substantially from the groupsof coils, the resilient wire between the coils and the ends of theresilient wire defining torque input arms relative to the return-bandloop, the resilient wire at each of its ends defining at least one coilwhich loosely engages the arch wire about the circumference of the archwire to hold the ends of the resilient wire relative to the arch wireand to substantially conform the elongate extent of the resilient wireto the curvature of the arch wire, conformance of the elongate extent ofthe resilient wire to the curvature of the arch wire torsion-allybiasing the resilient wire at the torque input arms thereof to producetorquing leverage on the tooth through engagement of the return-bendloop with the tooth when the system is in use, the torquing leveragebeing effective to pivot the tooth about the connection between the archwire and the bracket.

3. A structural system for effecting tilting selected ones of a personsteeth comprising, in combination, a metal band adapted. to be mountedaround each of the selected teeth, a bracket affixed to each band andadapted to extend anteriorly of the respective selected tooth, eachbracket defining a channel in its labial aspect, an arch wire extendingthrough the channels, means connected to each bracket retaining the archwire in the channel thereof, the arch wire extending laterally of thebrackets to ends spaced substantially from the brackets, means forattaching respective ends of the arch wire to two other teeth spacedfrom said selected teeth, the arch wire curving arcuatelybetween itsends, and a length of resilient Wire defining intermediate its ends twogroups of closely wound helical coils circumferentially of the archwire, the groups of coils loosely circumferentially engaging the archwire laterally of and proximate to the brackets mounted to the mostwidely spaced selected teeth, the resilient wire within its lengthbetween the groups of coils defining a plurality of return-bend loopscorresponding in number to the number of said selected teeth andextending laterally of the arch wire, the loops being adapted to bepositioned adjacent respective ones of the selected teeth and eachhaving a portion substantially parallel to the arch wire spaced from thearch wire a distance greater than the gingival edge of the bracket, theresilient wire between each loop of the plurality defining at least onecoil loosely engaging the arch wire about its circumference between thebrackets, the resilient wire extending from each group of coils awayfrom the return-bend loops along and in substantially parallel spacedrelation to the arch wire to ends of the resilient Wire spacedsubstantially from the groups of coils, the resilient wire between thegroups of coils and the ends of the resilient wire defining torque inputarms relative to the return bend loops, the resilient wire at each ofits ends defining at least one coil which loosely engages the arch wireabout the circumference of the arch Wire to hold the ends of theresilient wire relative to the arch wire and to substantially conformthe elongate extent of the resilient wire to the curvature of the archwire, conformance of the elongate extent of the resilient wire to thecurvature of the arch wire torsionally biasing the resilient wire at thetorque input arms thereof to produce torquing leverage on the tooththrough engagement of the return-bend loops with the selected teeth whenthe system is in use, the torquing leverage being effective to pivot theselected teeth about the connections between the arch wire and. therespective brackets.

4. An orthodontic appliance comprising an arch wire, and a length ofresilient wire, the resilient wire intermediate its ends defining twosets of closely wound coils, the sets of coils being spaced apart fromeach other and loosely engaging the arch wire the resilient wire betweenthe sets of coils defining a return-bend loop having spaced apart legsextending substantially directly from respective ones of the sets ofcoils to a portion of the loops spaced from the arch wire and connectingthe legs of the loop, the resilient wire extending from the sets ofcoils away from the loop to the ends of the resilient wire, theresilient wire adjacent each end thereof at a location spaced from theadjacent set of coils defining an additional coil loosely engaging thearch wire, the resilient wire between each set of coils and the adjacentadditional coil being spaced from the arch wire.

FOREIGN PATENTS 334,129 12/1958 Switzerland.

RICHARD A. GAUDET, Primary Examiner.

1. A STRUCTURAL SYSTEM FOR EFFECTING TILTING OF A PERSON''S TOOTHCOMPRISING, IN COMBINATION, A METAL BAND ADAPTED TO BE MOUNTED AROUNDTHE TOOTH, A BRACKET AFFIXED TO THE BAND AND ADAPTED TO EXTENDANTERIORLY OF THE TOOTH, THE BRACKET DEFINING A CHANNEL IN ITS LABIALASPECT, AN ARCH WIRE EXTENDING THROUGH THE CHANNEL, MEANS CONNECTED TOTHE BRACKET RETAINING THE ARCH WIRE IN THE CHANNEL, THE ARCH WIREEXTENDING LATERALLY OF THE BRACKET TO ENDS SPACED SUBSTANTIALLY FROM THEBRACKET, MEANS FOR ATTACHING RESPECTIVE ENDS OF THE ARCH WIRE TO TWOOTHER TEETH SPACED FROM SAID TOOTH, THE ARCH WIRE CURVING ARCUATELYBETWEEN ITS ENDS, AND A LENGTH OF RESILIENT WIRE DEFINING INTERMEDIATEITS ENDS TWO GROUPS OF HELICAL COILS CIRCUMFERENTIALLY OF THE ARCH WIRE,THE GROUPS OF COIL LOOSELY CIRCUMFERENTIALLY ENGAGING THE ARCH WIRELATERALLY OF AND PROXIMATE TO THE BRACKET, THE RESILIENT WIRE BETWEENTHE GROUPS OF COILS DEFINING A RETURN-BEND LOOP EXTENDING LATERALLY OFTHE ARCH WIRE, THE LOOP HAVING A PORTION SUBSTANTIALLY PARALLEL TO THEARCH WIRE SPACED FROM THE ARCH WIRE, THE RESILIENT WIRE EXTENDING FROMEACH GROUP OF COILS AWAY FROM THE RETURN-BEND LOOP ALONG AND IN SAPCEDRELATION TO THE ARCH WIRE TO ENDS OF THE RESILINET WIRE SPACEDSUBSTANTIALLY FROM THE GROUPS OF COILS, MEANS SECURING THE ENDS OF THERESILINET WIRE ARCH TO THE ARCH WIRE, CONFORMANCE OF THE ELONGATE EXTENTOF THE RESILIENT WIRE TO THE CURVATURE OF THE ARCH WIRE TORSIONALLYBIASING THE RESILIENT WIRE BETWEEN ITS ENDS AND THE GROUPS OF COILS TOPRODUCE TORQUING LEVERAGE ON THE TOOTH THROUGH ENGAGEMENT OF SAIDPORTION OF THE RETURN-BEND LOOP WITH THE TOOTH WHEN THE SYSTEM IS IN USEEFFECTIVE TO PIVOT THE TOOTH ABOUT THE CONNECTION BETWEEN THE ARCH WIREAND THE BRACKET.